BERLIN/BRUSSELS (Reuters) - Germany will press the Group of 20 to reaffirm its commitment to promoting free trade, resisting currency wars and fighting climate change when finance ministers meet next month for the first time since the election of Donald Trump, G20 sources said.

But the sources said there was far more uncertainty than usual surrounding the drafting of the G20 communique because of the Trump administration's confrontational rhetoric on trade and currencies, and its scepticism about whether humans are contributing to global warming.

Germany, which holds the rotating presidency of the G20, is in the awkward position of having to forge a consensus on a range of global issues without a clear sense of where Washington stands and amid pressure from China to push back against Trump's protectionist language.

"The Chinese want the G20 to reaffirm the importance of free trade, a cooperative financial order, and the fight against climate change," one German official told Reuters on condition of anonymity. "The challenge is to do this without giving it an anti-U.S. flavor."

The German government declined to comment.

The sources said it was too early to say whether there would be a major clash at the March meeting of finance ministers in the western spa town of Baden-Baden, describing the outcome as wide open.

But one G20 source said that Germany would push to preserve the essential elements of what has been agreed by the G20 in past years. Another source said currencies would "definitely be discussed".

In its 2016 communique, the G20 agreed to "refrain from competitive devaluations" or any targeting of exchange rates for "competitive purposes."

Trump and his advisers have repeatedly accused China of keeping its currency low to gain trade advantage.

And last month, Trump's trade adviser Peter Navarro accused Germany of exploiting other countries through a "grossly undervalued" euro, eliciting a sharp response from German officials, including Chancellor Angela Merkel.

Trump's appointee as Treasury Secretary, former banker Steve Mnuchin, has yet to be confirmed by the U.S. Senate and some German officials are expressing hope that he will take a more measured stance once in office.

Last month, in written responses to questions from the Senate Finance Committee, Mnuchin pointedly declined to say whether China was manipulating its yuan currency. He also said the Treasury would work with the G20 and other multilateral forums on currency issues.

Preliminary discussions between G20 sherpas have begun ahead of the March 17-18 meeting in Baden-Baden. But G20 sources say that no one in the U.S. administration is in a position to decide anything before Mnuchin and his top staff are in place.

The last G20 communique, agreed by leaders in Hangzhou, China in September, contains a number of statements which could sit uneasily with Trump administration policy.

The document voices support for a landmark agreement on fighting climate change reached in Paris in 2015, talks about the need for countries to "share in the burden" associated with refugee flows, and condemns terrorism "in all forms" but makes no specific reference to Islamist extremism, one of Trump's top priorities.

Trump's aggressive push for financial deregulation has also unsettled officials in countries like Germany and France. The G20 led the global push for tighter regulations on banks following the global financial crisis of 2008/9.

Germany's G20 presidency will culminate in a summit of leaders in Hamburg in July. Some German officials are expressing concern in private about whether Trump, who has promised to put "America First", will have the patience to sit around a table with other G20 leaders and engage in lengthy discussions about areas of multilateral coordination.